The present invention relates generally to storage systems and, more particularly, to system and method for improving the efficiency of applying a data transfer function such as remote copy to a data beyond the initial write input/output (I/O) operation of that data.
According to recent trends, the remote copy technology is one of the important technologies to continue or preserve business activities against a large-scale disaster. The remote copy technologies are classified broadly into two kinds, namely, synchronous and asynchronous. The synchronous remote copy is used between multiple datacenters which are spaced apart by distances that are not short distances. The asynchronous remote copy is used between multiple datacenters which are spaced apart by longer distances than those in the synchronous remote copy. For example, U.S. Pat. No. 7,152,079 discloses data replication among storage systems and, more specifically, asynchronous remote copy.
Heretofore, remote copy technologies typically require wide broad band network to transfer data. The data transfer occurs on initial copy, failback operation, and mirroring for write I/Os. However, generally the cost of data transfer between datacenters is expensive. Thus, it is desirable to reduce the traffic of remote copy. Traditionally, a user selects the volumes to apply the remote copy function and the remote copy function is not applied to the volumes that are not selected. The user may have variable data in one volume, and many of the volumes do not require the user to apply the remote copy function.